Two Degrees of Disaster

Two years ago, at a meeting in Copenhagen, world leaders agreed on the goal of limiting global warming to two degrees Celsius, or roughly three and a half degrees Fahrenheit. The so-called Copenhagen Accord, which Barack Obama personally helped negotiate, contained no mechanism for meeting this goal, so even though the President called it a “meaningful and unprecedented breakthrough,” many others questioned whether it was worth the proverbial paper it was printed on. Unfortunately, it now seems, the many others had a point.

On Wednesday, the Paris-based International Energy Agency released its annual “World Energy Outlook.” Among the report’s key findings is that, in spite of a shaky economy, global carbon-dioxide emissions rose by five per cent last year, to more than thirty billion metric tons. Meanwhile, energy efficiency—defined as the amount of energy used per unit of economic output—declined for the second year in a row. According to the I.E.A., “The door to 2°C is closing.” The group warned that unless dramatic action is taken by 2017, so many additional billions of tons of emissions will effectively be “locked in” that a temperature increase exceeding two degrees will become inevitable.

“If we don’t change direction soon, we’ll end up where we’re heading,” the report said.

One of the (many) obstacles to engaging the public on the issue of climate change is that, in the context of daily life, a temperature increase of two degrees Celsius (or even the larger number in Fahrenheit) sounds like no big deal. The problem, of course, is that daily life is a poor guide when the issue you’re dealing with is the global average. In that context, an increase of two degrees spells—at the very least—massive disruption. In fact, many scientists have warned that holding the average global temperature increase to “only” two degrees Celsius is a bit like limiting yourself to “only” a few rounds of Russian roulette: unless you’re uncommonly lucky, the result is not likely to be happy. As a group of climatologists put it on the blog RealClimate,

Even a “moderate” warming of 2°C stands a strong chance of provoking drought and storm responses that could challenge civilized society, leading potentially to the conflict and suffering that go with failed states and mass migrations. Global warming of 2°C would leave the Earth warmer than it has been in millions of years.

Meanwhile, other scientists have already turned their attention to a future beyond two degrees. Earlier this year, Britain’s Royal Society devoted an entire issue of its journal Philosophical Transactions of the Royal Society A to this topic. One of the articles in the issue posed the question “When could global warming reach 4°C?” (Which is to say, an increase of more than seven degrees Fahrenheit.) The answer, it concluded, was fairly soon. If the world continues on its current emissions path, then by the 2070s, the authors calculated, average global temperatures should be about four degrees higher than they were before the Industrial Revolution. If certain carbon “feedbacks” turn out to be stronger than currently predicted, then that four-degree rise could occur by the 2060s. A second article looked at what this might mean for society. The author, Rachel Warren, a researcher at the University of East Anglia, observed that in

a 4°C world, the limits for human adaptation are likely to be exceeded in many parts of the world, while the limits for adaptation for natural systems would largely be exceeded throughout the world.

Since we can’t know the future, it is possible to imagine that, either through better technology or more creativity or sheer necessity, our children will be able to find a solution that currently eludes us. Somehow or other, they will figure out a way to avoid “a 4°C world.” But to suppose that an answer to global warming can be found by waiting is to misunderstand the nature of the problem. Once you’ve dumped CO2 into the atmosphere, there’s no getting it back, at least not on a human timescale. When it comes to global warming, the future really is now.

Meanwhile, even if it’s only self-interest in the narrowest possible sense that moves people, global warming still ought to be high on almost everybody’s list of concerns. Between here and 4°C, or now and the 2070s, there are all sorts of potential calamities of which the punishing drought in Texas, the flooding in Thailand, and the famine that has recently killed tens of thousands of Somalis are just a foretaste.

Later this month, representatives from around the world will meet in Durban for another round of international climate negotiations. Because all of the trends have been heading in the wrong direction since Copenhagen, the expectation is that little will be accomplished. But, of course, the direction of the trends is precisely why urgent steps are needed. As the new I.E.A. report points out, delaying action on climate change is a “false economy”; every dollar we don’t spend today, we will end up spending several times over in a much hotter, more dangerous world.

Photograph by Nicolas Asfouri/AFP/Getty Images

Elizabeth Kolbert has been a staff writer at The New Yorker since 1999.